Installation and a process for lubricating, cleaning and/or disinfecting conveyor belts

ABSTRACT

An installation for lubricating, cleaning and/or disinfecting conveyor belts for containers, more particularly for foods, such as bottles, glasses, cans, bags and the like, comprising a central metering station connectable to a water pipe used to dilute a concentrated lubricant, cleaner or disinfectant, and several distributing pipes connected to the metering station lead to the points of use. At each point of use there is a mixing valve (13-19) connectable to distribution line (52) and the water pipe (23) and individually adjustable for each point of use and a pressure reducer (50, 51) fitted upstream of each mixing valve. Varying concentration can be provided for each point of use (31-37) with little technical complexity. In another embodiment, the invention is the process carried out by the installation.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to an installation for lubricating, cleaningand/or disinfecting conveyor belts for containers, more particularly forfoods, such as bottles, glasses, cans, bags and the like. Theinstallation comprises at least one central metering station--designedfor connection to a water pipe--for diluting a concentrated lubricant,cleaner or disinfectant and several distributing pipes connected to themetering stations and leading to the points of use.

2. Description of the Related Art

In the food industry, the food containers, for example beverage bottles,are transported on conveyor belts, more particularly slat belts, hingedchains and the like. Thus, beverage bottles have to be transported fromthe unpacking station to the washing machine, to the filler, to thelabeling machine and to the packing station. In the beverage industry,for example in breweries, the washing, filling and labeling of bottlesis mainly carried out automatically. Accordingly, the high-speedconveyor belts, which are made of stainless steel or plastic, have to belubricated with a chain lubricant which is also known as a "beltlubricant". In addition, the conveyor belts have to be cleaned and/ordisinfected at more or less regular intervals. The necessaryconcentration of the chain lubricant depends on a number of parameters,including for example the belt speed, the surface quality and theloading of the belts. For this reason, different concentrations have tobe used depending on where the lubricant is applied.

The present state of the art in belt lubrication is described in detailin an article in the journal "Brauwelt", Vol 131 (1991), No. 44, pages2026-2032. Reference is made to that article to complete the disclosureof the present invention.

The cleaners, disinfectants and belt lubricants are supplied asconcentrates by the manufacturers and, in the food-processing plant, areapplied to the conveyor belt, for example by spraying, after dilutionwith water to the particular in-use concentration required. The solutionthen runs off the belt into a wastewater channel via a collector.

The solution to be used with the particular concentration required maybe prepared from the concentrate as supplied by the manufacturer invarious ways. Thus, the concentrates may be taken to the points of use,diluted with water to the particular in-use concentration and directlyused. Various metering systems, for example injectors, metering pumps orother volume- or time-controlled and quality-controlled systems, may beused for dilution. However, the concentrates have to be transported tothe particular points of use within the plant and separate meteringsystems have to be provided for each point of use.

Although the concentrate could in principle be transported from thechemicals storeroom to the points of use through a pipe, this would notbe appropriate because the corresponding concentrate--as awater-endangering and caustic liquid--should not be transported throughproduction rooms and work rooms. In addition, the blending of two liquidstreams in a ratio of 1:200 to 1:1000 through a blending valve istechnically very complicated if it is to be carried out with thenecessary accuracy.

In another variant, the concentrates are diluted to the required in-useconcentration in a central metering station. The solution thus preparedis then transported to the points of use through distributing pipes. Thepresent invention is concerned with the further development of suchcentral conveyor belt lubrication systems. Various concentrations of thesolutions intended for the individual points of use are possible, but dorequire several central metering stations which transport the solutionsto the conveyor belts through separate distributing pipes. Thisrequirement means additional expenditure on metering technology andpipes.

With a conventional metering system based on diaphragm metering,cleaning, disinfecting and belt lubricating solutions intended fordirect throughputs of 5 m³ /hour or higher are extremely difficult toprepare with a uniform distribution of concentration for variable flowrates.

This is attributable above all to the limited metering frequency of thediaphragm metering pumps. When the maximum metering frequency isreached, a higher throughput of the in-use solution with the necessaryconcentration can only be achieved by increasing the amount added duringeach individual stroke of the diaphragm pump. As a result, theproportional amount added cannot be uniformly mixed in the pipe.

SUMMARY OF THE INVENTION

The problem addressed by the present invention was to provide aninstallation for the lubrication, cleaning and/or disinfection ofconveyor belts which would enable the in-use solution to be adjusted tothe different concentrations required for the different points of use atonly minimal expense by comparison with the prior art.

In an installation of the type mentioned at the beginning, the solutionto this problem as provided by the invention is characterized in that amixing valve designed for connection to the distributing pipe and to thewater pipe and for individual adjustment for each point of use and apressure reducer preceding each mixing valve are provided at each pointof use. A uniformly mixed stock solution and hence in-use solution isobtained even at high throughputs. This is because the stock solution isprepared with a relatively high concentration and at a relatively lowthroughput so that the metering pulse/interval in the pipe isconsiderably shortened, the miscibility of the concentrates in the pipeis improved and on-line metering is thus possible. There is no longerany need for cumbersome and high-cost tanks for preparing and mixing thesolution or for expensive metering techniques.

The pressure reducer preceding the mixing valve in each stock solutionand water supply pipe equalizes any pressure variations in the feedsystems. The adjustable, defined pressure ratio between the componentsto be mixed provides for a constant mixture concentration after themixing valve.

In addition, the use of stock solutions and the fact that they are mixedwith water at the point of use considerably reduces the pipe lengths ofthe distributing pipe system in relation to the prior art with itscentral metering station because there is no longer any need for aseparate metering station with a separate pipe to the point of use foreach separately prepared, different in-use concentration. The minimalcapital investment in relation to the prior art provides for the use ofconcentrations differing according to the points of use even in thosecases where, hitherto, only one concentration was used on economicgrounds.

The cost of the pipework for the mixing water system is minimal comparedwith the laying of several pipes for the in-use solution because themixing water can be taken from existing rinsing water systems or fromthe fresh water supply. In addition, only one pipe system is requiredfor mixing several concentrations.

Accordingly, the invention enables different concentrations of thecleaner, disinfectant and belt lubricant to be used. The in-useconcentration can always be adjusted and varied in situ to fulfillrequirements in regard to soiling, disinfection regulations and thespecific belt lubrication requirements. Since the concentration of thein-use solution can be individually adjusted for each point of use, theconcentrates can be economically used without over- or underdosage.

Depending on the length of the pipe for the in-use solution after themixing valve, on its cross-section and on the flow rate of the in-usesolution, it may be favorable for the mixing valve to be followed by astatic mixer. The specific conditions prevailing at the point of use arealso key factors in the choice of this additional static mixer. Toestablish the concentrations according to operating requirements, it isof advantage to provide a manually or automatically operable controlelement at the mixing valve to adjust the mixing ratio. In this way, theinstallation can be adapted to changing operating conditions.

The component streams are prevented from flowing back by the provisionof non-return valves in the water connection and in the supply pipe forstock solution.

The invention also relates to a process for mixing, cleaning and/ordisinfecting conveyor belts for containers, more particularly for foods,such as bottles, glasses, cans, bags and the like, in which aconcentrated lubricant, cleaner or disinfectant is diluted with water ina central metering station and the resulting in-use solution istransported to various points of use where it is applied to theparticular conveyor belt.

In this process, the solution to the problem stated above ischaracterized in that the concentrate is prediluted in a centralmetering station to form a stock solution which has at least the highestconcentration required at the point of use and is only diluted withwater at the point of use to the concentration required there in orderto obtain the in-use solution.

The stock solution must have at least the highest concentrationsrequired at the points of use. In a particularly favorable embodiment,however, the concentration of the stock solution is adjusted to betweenthree and six times the concentration required at the points of use.

Depending on the design of the pipe systems and the flow rate of thein-use solution, it can be of advantage uniformly to mix the in-usesolutions, for example in a static mixer, before they are applied to theconveyor belt at their point of use. In other cases, a uniformconcentration is not necessary or may even be established withoutadditional measures by virtue of the predetermined process conditions.

To prepare a solution of belt lubricant, a relatively small centralmetering station is installed in the chemicals storeroom and the stocksolution is transported to the lubrication circuits of the conveyors. Amixing valve is associated with each lubrication circuit. Differentin-use concentrations can thus be established to meet variouslubrication requirements and thus to fulfill the various operating andhygiene standards which the conveyor zones are expected to meet.

The process according to the invention and the installation according tothe invention may also be used for the centralized preparation ofcleaning and disinfecting solutions and for their application in thefood industry, for example for "hidden" foam cleaning tasks.

A constant cleaning and disinfecting solution is prepared as a stocksolution in a central chemicals room, transported to the decentralizedcleaning stations via a distributing pipe system and diluted with waterto the necessary in-use concentration via the mixing valve. Theconcentration of the in-use solution may be individually adjusted foreach particular field of application so that the various cleaning anddisinfection requirements can be optimally satisfied.

BRIEF DESCRIPTION OF THE DRAWINGS

Examples of embodiment of the invention are described in detail in thefollowing with reference to the accompanying drawings, wherein:

FIG. 1 is a process flow chart for a belt lubrication system.

FIG. 2 is a process flow chart for a centralized cleaning system.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The spray system for applying the belt lubricant in FIG. 1 is divided upinto various lubrication circuits according to the various conveyorsections. Seven lubrication circuits are provided and are each suppliedwith belt lubricating solution through feed pipes 1 to 7. Hitherto,these various lubrication circuits were either supplied with solutionsof only one concentration or a separate metering station 8 to 10 wasrequired for each lubrication circuit, as shown in chain lines.

Since different in-use concentrations are being required to anincreasing extent for the various lubrication circuits in practice, theinvention affords the possibility of preparing these concentrations withless outlay on equipment than before as follows:

In a chemicals storeroom, a stock solution is prepared by proportionalmetering (pulse water meter 12 and metering pump 11) and is delivered tothe various lubrication circuits through a distributing pipe system. Thestock solution has a concentration, for example 1%, which corresponds toaround 3 to 6 times the in-use concentration. Before the pipe divides ateach lubrication circuit to form the spray system, a mixing valve 13 to19 is installed in this new process and dilutes the stock solutionprepared in the chemicals storeroom to the required concentration withfresh water from a second branch pipe system 20.

In addition, FIG. 1 shows the concentrate tank 21 in the chemicalsstoreroom, a first fresh water connection 22, a second fresh waterconnection 23, the magnetic valves 24 to 30 provided for eachlubricating circuit, the spray systems 31 and 32 with concentrations of0.1 and 0.2% for the box conveyor, the spray system 33 for the dirtybottles, the spray systems 34 and 35 for the empty bottles, the spraysystems 36 and 37 for the full bottles and the distributing pipe 52 forthe stock solution. The concentrations are shown in FIG. 1.

The components of the installation are installed in such a way that

no product or water can enter the other distributing pipe system,

different system pressures in the branch pipe systems do not have anyeffect on the required concentration (to this end, the mixing valves 13to 19 are preceded by pressure reducers 50, 51),

different consumptions/throughputs do not affect the mixtureconcentration,

the mixture concentration is kept constant within narrow limits (±5% ofthe required concentration),

the mixing valve can be manually or automatically adjusted to variousmixture concentrations and

the mixing valve can be adapted to the particular throughput.

Depending on practical requirements, a static mixer may be installedafter the mixing valve.

After the mixing valves 13 to 19, the belt lubrication system isdelivered to the spray systems 31 to 37 of the particular lubricationcircuits through magnetic valve controls 24 to 30.

In this example of belt lubrication, different concentrations arerequired in the various lubrication circuits because

different lubrication requirements have to be satisfied;

there are differences in the demand for disinfection in the variouszones;

dilution by process liquids on belts require different concentrations;

specific functions of the installation require special lubricantconcentrations.

The invention is explained once again for another application withreference by way of example to preparation of the cleaner (FIG. 2). Thereference numerals in FIG. 2 have the same meaning as in FIG. 1.

The above-mentioned cleaning systems in the food industry requiredifferent concentrations of cleaner according to the degree of soilingof the installations. If the cleaning solution were to be centrallysupplied from a chemicals storeroom, this would mean that eachconcentration required would need a separate metering station whichwould prepare the solution concentration and which would be connected tothe consumer (article to be cleaned) by a long distributing pipe system(chain-line illustration).

According to the present invention, a stock solution is prepared byproportional metering with a concentration around 3 to 6 times higherthan the required concentration and is delivered to the articles to becleaned. At each of the articles 38 to 40 to be cleaned, the stocksolution is individually diluted to the required concentration (in-useconcentration) and processed via the mixing valve 13 to 18. Theprinciple involved is identical with the mixing of belt lubricatingsolutions. The articles to be cleaned are: filler (outside) 38, bottlewashing machine 39, conveyors 40, external tank cleaning 41, walls andfloors 42, shelves 43. The references 44 to 49 denote the removal valvesbefore which air can be introduced into the pipe as required.

The invention affords the following advantages:

simple and inexpensive metering system for preparing the stock solution;

low capital investment for the distributing pipe for stock solution;

individual adjustment of the concentration of the cleaner at eacharticle through utilization of the centralized supply of chemicals.

An alternative not covered by the invention would be the preparation ofindividual concentrations in situ at the articles or conveyors to becleaned. However, this would have the disadvantage that theconcentrate--as an aggressive and water-endangering liquid--would haveto be transported through metering pipes in the plant which wouldincrease the potential risk involved in handling these products.

In addition, this alternative would require greater capital investmentin metering and measuring systems (water throughflow, empty signals), incabling and assembly work and in maintenance and servicing in relationto the present invention with its hydraulic mixing valves.

LIST OF REFERENCED NUMERALS

1-7 Feed pipes

8-10 Metering stations according to the prior art

11 Metering pump

12 Pulse water meter

13-19 Mixing valves

20 Second branch pipe system

21 Concentrate tank

22 First fresh water connection

23 Second fresh water connection

24-30 Magnetic valves

31-37 Spray systems

38 Filler, outside

39 Bottle washing machine

40 Conveyors

41 External tank cleaning

42 Walls, floors

43 Shelves

44-49 Removal valves

50, 51 Pressure reducers

52 Distributing pipe for stock solution

The invention claimed is:
 1. An installation for cleaning, lubricating,and/or disinfecting a conveyor belt comprising:at least one meteringstation configured to couple to a diluting fluid source, to dilute aconcentrated material and provide a treatment fluid containing a desiredconcentration of the material to a distribution pipe system; a pluralityof mixing valves, coupled in parallel to the distribution pipe system,such that each mixing valve receives some of the treatment fluid fromthe distribution pipe system and diluting fluid from a diluting fluidsource and mixes said some of the treatment fluid with the dilutingfluid to provide a further diluted fluid to a respective point of use,the desired concentration of the material in the treatment fluid beingabout 3 to about 6 times that of a concentration of the material in thefurther diluted fluid; and at least one of the following:a firstpressure reducing valve, which regulates a pressure at which thediluting fluid is delivered to said at least one metering station, tosubstantially prevent the concentration of the material in the treatmentfluid from changing due to changes in pressure of the diluting fluid; ora second pressure reducing valve, which regulates a pressure at whichthe diluting fluid is provided to the plurality of mixing valves.
 2. Aninstallation as claimed in claim 1, further comprising at least onestatic mixer disposed between a respective one of said mixing valves andits respective point of use, to mix the further diluted fluid.
 3. Aninstallation as claimed in claim 1, wherein each mixing valve furthercomprises a manually or automatically operable control element forestablishing the mixing ratio of the diluting fluid and the treatmentfluid for each of said mixing valves.
 4. An installation as claimed inclaim 1, further comprising a magnetic valve prior to each point of usefor regulating the total flow of the further diluted fluid to itsrespective point of use.
 5. An installation as claimed in claim 1,further comprising a removal valve, prior to each point of use, which isconfigured to introduce an outside atmosphere into the further dilutedfluid.
 6. An installation as claimed in claim 1, comprising said firstand second pressure reducing valves.
 7. A process for cleaning,disinfecting and/or lubricating a conveyor belt, comprising the stepsof:diluting a concentrated material with a diluting fluid at a firstmixing location to produce a treatment fluid containing a desiredconcentration of material; distributing the treatment fluid to aplurality of second mixing locations coupled in parallel to adistribution pipe system; mixing a diluting fluid with the treatmentfluid at each of the second mixing locations to provide a furtherdiluted fluid from said each of the mixing locations to respectivepoints of use at the conveyor belt; and at least one of thefollowing:regulating the pressure at which the diluting fluid isprovided to the first mixing location to substantially prevent changesin the diluting fluid pressure from changing the concentration of thematerial in the treatment fluid; or regulating the pressure at which thediluting fluid is provided to the second mixing locations; wherein saidstep of diluting results in the concentration of the material in thetreatment fluid being between about 3 and about 6 times that of aconcentration of the material in the further diluted fluid required atthe points of use.
 8. A method as claimed in claim 7, further comprisingthe step of adjusting the mixing ratio of the diluting fluid and thetreatment fluid.
 9. A method as claimed in claim 7, further comprisingthe step of static mixing the further diluted fluid prior to applyingthe further diluted fluid to the conveyor belt at the points of use. 10.A method as claimed in claim 7, comprising both of the regulating steps.11. An installation for cleaning, lubricating, and/or disinfecting aconveyor belt comprising:at least one metering station configured tocouple to a diluting fluid source, to dilute a concentrated material andprovide a treatment fluid containing a desired concentration of thematerial to a distribution pipe system; a plurality of mixing valves,coupled in parallel to the distribution pipe system, such that eachmixing valve receives some of the treatment fluid from the distributionpipe system and diluting fluid from a diluting fluid source and mixessaid some of the treatment fluid with the diluting fluid to provide afurther diluted fluid to a respective point of use; a removal valve,prior to each point of use, which is configured to introduce an outsideatmosphere into the further diluted fluid; and at least one of thefollowing:a first pressure reducing valve, which regulates a pressure atwhich the diluting fluid is delivered to said at least one meteringstation, to substantially prevent the concentration of the material inthe treatment fluid from changing due to changes in pressure of thediluting fluid; or a second pressure reducing valve, which regulates apressure at which the diluting fluid is provided to the plurality ofmixing valves.